CDC25B is a phosphatase playing an important role in determining G2/M phase transition during cell division. Inhibition of CDC25B activity hinders cell division, and consequently, results in cell death; that is, it is related with anticancer action. Hyperexpression of CDC25B was observed in most tumors including stomach cancer (Jpn. J. Cancer Res. 1997, 88, 9947), colon cancer (Exp. Cell Res. 1998, 240, 236; Lab. Invest. 2001, 81, 465), lung cancer (Cancer Res. 1998, 58, 4082), brain cancer and laryngeal cancer (Cancer Res. 1997, 57, 2366), breast cancer (Cancer Statistics in Japan 1997 Foundation for Promotion of Cancer Research, Tokyo, Jpn.), etc. Abnormal proliferations of mammary glands were observed in a transgenic mouse in which CDC25B was over-expressed (Oncogene 1999, 18, 4561). It was also reported that breast cancer is easily induced when treated with a carcinogen (9,10-dimethyl-1,2-benzanthracene) to the transgenic mouse. Accordingly, CDC25B is an important target in developing an anticancer agent. That is, development of an anticancer agent capable of inhibiting CDC25B with little cytotoxicity to normal cells will be desirable.
EP 379979 A1 discloses that a 5-(substituted-1H-pyrazol-4-ylmethylene)-thiazolidine-2,4-dione derivative, with the pyrazole group at the 5-position of the thiazole having a pyrazolopyridine structure, can be used as adenosine antagonist.
Japanese Patent No. 55029804 discloses that the silver halide of a 5-(substituted-1H-pyrazol-4-ylmethylene)-thiazolidine-2,4-dione derivative, with the pyrazole group at the 5-position of the thiazole having a pyrazolone structure, is useful as a dye that inhibits blurring and photoemission in a photosensitizer.